Synergistic preservative/personal care composition containing an alkylene glycol ester

The present application is the National Stage entry of International Patent Application No. PCT/EP2021/060549, filed on Apr. 22, 2021, which is based on and claims priority to European Patent application Serial No. 20 171 210.6, filed on Apr. 23, 2020.

The present invention relates to a preservative composition containing a preservative agent and a potentiator ingredient with enhance preservative properties as compared with a preservative composition with a preservative agent itself.

Microbial contamination of personal care products, cosmetics, home care products and other similar products is a matter of great importance to the personal care industry. Microbial contamination can become a major cause of product losses of end-use formulations and can cause significant economic loss. Further, contamination of cosmetics and home care products can result in their being converted into products that are hazardous for consumers. Certain, preservative agents and preservative compositions for protecting against microbial attack either from bacterial or fungal sources are known in the art. These preservative agents have a wide variety of applications in fields such as personal care products, cosmetics, home care products, and health and hygiene products.

There are continued regulatory pressures to reduce the amount of the preservative agent(s) in end-use formulations. Similarly, in the field of personal care formulations there are ongoing regulatory pressures to reduce the amount of the active ingredient in personal care formulations. Additionally, there are continued regulatory pressures to stop using certain conventional preservatives or to reduce the amount of certain conventional preservatives in end-use formulations.

Accordingly, a need exists for preservative compositions that contain less active ingredient or preservative while maintaining acceptable levels of overall antimicrobial efficacy.

Provided herein is a synergistic mixture of a preservative agent with an alkylene glycol ester compound which can be used in various compositions, including personal care formulations.

In one aspect, provided is a preservative composition containing a (i) preservative agent; and (ii) an alkylene glycol ester, wherein the alkylene glycol ester is present in an amount to sufficiently increase the efficacy of the preservative agent as compared to the preservative agent alone, and the increase is greater than the additive effect of the biocidal activity of the preservative agent and alkylene glycol ester taken alone.

In another aspect, provided is a preservative composition according wherein the weight ratio of the alkylene glycol ester to the preservative agent, for instance, can be in the range of about 1:50,000 to about 500:1, such as from about 1:10,000 to about 300:1, such as from about 1:5,000 to about 10:1, such as from about 1:2,500 to about 8:1, such as from about 1:1,500 to about 2:1. In many applications, only a small amount of alkylene glycol ester is needed in order to enhance the efficacy of the preservative agent. For example, in one aspect, the preservative agent is present in greater amounts than the alkylene glycol ester. In certain embodiments, the weight ratio of the alkylene glycol ester to the preservative agent can be from about 1:5,000 to about 4:1, such as from about 1:1,500 to about 4:1, such as from about 1:300 to about 4:1, such as from about 1:20 to about 4:1, such as from about 1:15 to about 4:1, such as from about 1:10 to about 4:1.

In another aspect, the preservative composition has a preservative agent which is an acid compound, an aldehyde, a phenolic compound, a sulfite, an iron chelator, an aromatic alcohol, a quaternary ammonium compound, a pyrone compound, a urea compound, an imidazole compound, an isothiazolinone compound, an amine such as a triamine or a combination of two or more preservative agents.

In a particular aspect, the preservative composition has a preservative agent containing an iron chelator, said iron chelator comprises a pyrithione compound, piroctone olamine, 2-pyridinol-1-oxide, N-hydroxy-6-octyloxypyridine 2(1H)-one, -hydroxy-6-octyloxypyridine 2(1H)-one ethanolamine salt or a mixture thereof. Particular pyrithione compounds include zinc pyrithione, sodium pyrithione or mixtures thereof.

In an embodiment of the present invention, the preservative agent is an acid compound. The acid compound may be an acid, an ester of an acid or a salt of an acid. In a particular embodiment, the acid compound comprises benzoic acid, propionic acid, salicylic acid, sorbic acid, formic acid, undec-10-enoic acid, lactic acid, glycolic acid, and citric acid, or a salt thereof.

In another embodiment, the preservative agent is a quaternary ammonium compound. Particular quaternary ammonium compounds include an alkyl (C12-22) trimethyl ammonium compound, a benzethonium compound, or a mixture thereof.

In a further embodiment, the preservative agent comprises an alcohol. Alcohols may include lower alkyl alcohols or aromatic alcohols. A particular aromatic alcohol is phenoxy ethanol and a particular lower alcohol is isopropanol.

In another aspect, the alkylene glycol ester can be a monoalkylene glycol ester, a dialkylene glycol ester, a trialkylene glycol ester or mixtures thereof. The alkylene glycol ester can be formed from a C1 to C6 alkylene, such as ethylene, propylene, or butylene. The alkylene glycol ester can be a monoester, a diester, or mixtures thereof and can be derived from (a) an alkylene glycol, and (b) a fatty acid comprising, for example, a caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, or palmitic acid. Particular examples of such alkylene glycol esters include one or more of an alkylene glycol isostearate, an alkylene glycol laurate, an alkylene glycol myristate, an alkylene glycol oleate, an alkylene glycol monolaurate, an alkylene glycol monocaprate, an alkylene glycol monocaprylate, an alkylene glycol caproate, an alkylene glycol diperlargonate, an alkylene glycol diisostearate, an alkylene glycol dilaurate, an alkylene glycol monopalmitate, an alkylene glycol monostearate, an alkylene glycol decanoate, or mixtures thereof, other complexes or derivatives thereof, and the like. The alkylene group in the above examples can be one or more propylene groups, ethylene groups or butylene groups. In one embodiment, at least one alkylene glycol monoester is incorporated into the composition.

In another aspect of the present invention, provided is method for increasing the efficacy of a preservative agent in an end-use formulation. The method contains the steps of providing a preservative agent and an effective amount of an alkylene glycol ester. The preservative agent and alkylene glycol ester can be added to an end-use formulation to increase the efficacy of the preservative agent as compared to an equal amount of preservative agent without the alkylene glycol ester. The alkylene glycol ester may be added to the preservative agent prior to the addition of the preservative agent to the end-use formulation, after the preservative agent is added to the end-use formulation, prior to the addition of the preservative agent to the end-use formulation, or concurrently with the preservative agent to the end-use formulation.

In a further aspect of the present invention, provided is a method of increasing the resistance of an end-use formulation to biological attack. The method includes providing a cosmetic formulation and adding a preservative composition in any one of the previous aspects or embodiments to the cosmetic formulation. By adding the preservative composition, the end use composition has an increased resistance to biological attack as compared to an end-use formulation without the alkylene glycol ester present in the preservative composition.

In a further aspect of the present invention, provided is a method of reducing the minimum amount of preservative agent needed for effective preservation activity in an end-use formulation. The method includes providing a preservative agent and adding an amount of an alkylene glycol ester to the preservative agent to form a preservative composition. The preservative composition can then be added to an end-use formulation, wherein the minimum amount of the preservative agent needed for effective preservation activity in the end-use formulation is less than if the preservative agent was used alone.

In a further embodiment, provided is an end-use formulation containing a preservative composition of any of the prior embodiments. The end-use formulation may be a personal care formulation or a home care formulation.

In a further aspect, the present invention provides a preservative composition comprising (i) a preservative agent selected from the group consisting of phenoxyethanol, bis (3-aminopropyl) dodecylamine, didecyl dimethyl ammonium chloride, sodium benzoate, lactic acid, benzyl alcohol, benzisothiazolinone, sorbic acid, and dehydroacetic acid, or a salt thereof; and (ii) at least one alkylene glycol ester derived from (a) an alkylene glycol, and (b) a fatty acid having from about 6 to 14 carbon atoms, wherein the at least one alkylene glycol ester is present in an amount to sufficiently increase the efficacy of the preservative agent as compared to the preservative agent alone.

In one embodiment, the preservative agent is phenoxyethanol and preferably the phenoxyethanol and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 6:1 to 1:1, preferably of from 3:1 to 1:1, more preferably of from 2:1 to 1:1.

In one embodiment, the preservative agent is bis (3-aminopropyl) dodecylamine and preferably the bis (3-aminopropyl) dodecylamine and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 25:1 to 1:25, preferably of from 20:1 to 1:20, more preferably of from 15:1 to 1:15.

In one embodiment, the preservative agent is didecyl dimethyl ammonium chloride and preferably the didecyl dimethyl ammonium chloride and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 25:1 to 1:25, preferably of from 20:1 to 1:20, more preferably of from 15:1 to 1:15.

In one embodiment, the preservative agent is sodium benzoate and preferably the sodium benzoate and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 50,000:1 to 50:1, preferably of from 10,000:1 to 100:1, more preferably of from 5000:1 to 150:1.

In one embodiment, the preservative agent is lactic acid and preferably the lactic acid and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 250:1 to 1:1, preferably of from 220:1 to 1:1, more preferably of from 200:1 to 2:1.

In one embodiment, the preservative agent is benzyl alcohol and preferably the benzyl alcohol and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 800:1 to 1:1, preferably of from 600:1 to 2:1, more preferably of from 400:1 to 3:1.

In one embodiment, the preservative agent is benzisothiazolinone and preferably the benzisothiazolinone and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 40:1 to 1:4, preferably of from 60:1 to 1:3, more preferably of from 40:1 to 1:2.

In one embodiment, the preservative agent is sorbic acid and preferably the sorbic acid and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 100:1 to 1:4, preferably of from 80:1 to 1:3, more preferably of from 60:1 to 1:2.

In one embodiment, the preservative agent is dehydroacetic acid and preferably the dehydroacetic acid and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 1000:1 to 10:1, preferably of from 800:1 to 15:1, more preferably of from 600:1 to 20:1.

In one embodiment, the present invention provides a preservative composition comprising (i) a preservative agent, wherein the preservative agent comprises phenoxyethanol; and (ii) at least one alkylene glycol ester derived from (a) an alkylene glycol, and (b) a fatty acid having from about 6 to 14 carbon atoms, wherein the at least one preservative agent and the alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 1:1 to 6:1.

In one embodiment, the preservative agent is phenoxyethanol.

In one embodiment, the at least one alkylene glycol ester is a propylene glycol ester or a mixture of propylene glycol esters derived from (a) propylene glycol, and (b) a fatty acid having from about 6 to 14 carbon atoms. In one embodiment, the fatty acid is selected from the group consisting of caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, and combinations thereof. In one embodiment, the at least one alkylene glycol ester is a monoester, a diester, or a combination thereof. In one embodiment, the at least one alkylene glycol ester comprises propylene glycol monocaprylate, propylene glycol dicaprylate, or a combination thereof.

In one embodiment, the phenoxyethanol and the at least one alkylene glycol ester are comprised in the preservative composition at a weight ratio of from 1:1 to 2:1, preferably at a weight ratio of from 1.2:1 to 1.8:1, and more preferably at a weight ratio of from 1.4:1 to 1.6:1.

In one embodiment, the at least one alkylene glycol ester comprises propylene glycol caprylate.

In one embodiment, the at least one alkylene glycol ester comprises a mixture of at least one propylene glycol monocaprylate and propylene glycol dicaprylate. In one embodiment, the at least one alkylene glycol ester consists of a mixture of at least one propylene glycol monocaprylate and propylene glycol dicaprylate.

In one embodiment, the at least one propylene glycol monocaprylate and the propylene glycol dicaprylate are comprised in the mixture at a weight ratio of from 15:1 to 1:1, preferably at a weight ratio of from 10:1 to 1:1, more preferably at a weight ratio of from 5:1 to 2:1.

In one embodiment, the phenoxyethanol and the mixture of at least one propylene glycol monocaprylate and propylene glycol dicaprylate are comprised in the preservative composition at a weight ratio of from 1:1 to 2:1, preferably at a weight ratio of from 1.2:1 to 1.8:1, and more preferably at a weight ratio of from 1.4:1 to 1.6:1.

In one embodiment, the at least one alkylene glycol ester comprises at least 50% by weight of at least one propylene glycol monocaprylate, preferably at least 60% by weight of at least one propylene glycol monocaprylate, more preferably at least 70% by weight of at least one propylene glycol monocaprylate, based on the total weight of the at least one alkylene glycol ester.

In one embodiment, the at least one propylene glycol monocaprylate is selected from octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate, and a combination thereof; and/or the propylene glycol dicaprylate is 1,2-propylene glycol dicaprylate.

In one embodiment, the at least one alkylene glycol ester comprises a mixture of octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate, and 1,2-propylene glycol dicaprylate. In one embodiment, the phenoxyethanol and the mixture of octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate and 1,2-propylene glycol dicaprylate are comprised in the preservative composition at a weight ratio of from 1:1 to 2:1, preferably at a weight ratio of from 1.2:1 to 1.8:1, and more preferably at a weight ratio of from 1.4:1 to 1.6:1.

In one embodiment, the preservative composition of the present invention comprises (i) phenoxyethanol; and (ii) a mixture of octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate and 1,2-propylene glycol dicaprylate; wherein the phenoxyethanol and the mixture of octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate and 1,2-propylene glycol dicaprylate are comprised in the preservative composition at a weight ratio of from 1:1 to 2:1, preferably at a weight ratio of from 1.2:1 to 1.8:1, and more preferably at a weight ratio of from 1.4:1 to 1.6:1.

In one embodiment, the preservative composition of the present invention comprises (i) from 45 wt.-% to 70 wt.-% preservative agent, wherein the preservative agent comprises phenoxyethanol; and (ii) from 25 wt.-% to 50 wt.-% of at least one alkylene glycol ester derived from (a) an alkylene glycol, and (b) a fatty acid having from about 6 to 14 carbon atoms; wherein the amounts are based on the total weight of the preservative composition.

In one embodiment, the preservative composition of the present invention comprises (i) from 45 wt.-% to 70 wt.-% phenoxyethanol; and (ii) from 25 wt.-% to 50 wt.-% of a mixture of octanoic acid-2-hydroxy-1-methylethyl ester, 2-hydroxylpropyl caprylate and 1,2-propylene glycol dicaprylate; based on the total weight of the preservative composition.

In a further aspect, the present invention provides a personal care product comprising the preservative composition according to the present invention. In one embodiment, the at least one alkylene glycol ester comprised in the preservative composition is present in the personal care product in an amount of from 1 wt.-% or less, such as in an amount of 0.5 wt.-% or less, based on the weight of the personal care product.

In a further aspect, the present invention provides an end-use formulation comprising the preservative composition according to the present invention.

In a further aspect, the present invention provides the use of the preservative composition according to the present invention for increasing the efficacy against microorganisms compared to an equal amount of the preservative agent without the at least one alkylene glycol ester. In one embodiment, the efficacy is increased by at least 0.5 log reduction. In one embodiment, the efficacy is increased by at least 1.0 log reduction.

In a further aspect, the present invention provides a method for preventing a personal care product from spoilage by microorganisms, the method comprising adding the preservative composition according to the present invention to the personal care product.

In a further aspect, the present invention provides a method for increasing the efficacy of a preservative agent against microorganisms in an end-use formulation, said method comprising providing an end-use formulation and a preservative agent, adding an effective amount of an at least one alkylene glycol ester to the preservative agent and end use formulation to increase the efficacy of the preservative agent in the end-use formulation, as compared to an equal amount of preservative agent without the at least one alkylene glycol ester in the end-use formulation, wherein the preservative agent is selected from the group consisting of phenoxyethanol, bis (3-aminopropyl) dodecylamine, didecyl dimethyl ammonium chloride, sodium benzoate, lactic acid, benzyl alcohol, benzisothiazolinone, sorbic acid, and dehydroacetic acid, or a salt thereof; and wherein the at least one alkylene glycol ester is derived from (a) an alkylene glycol, and (b) a fatty acid having from about 6 to 14 carbon atoms. In one embodiment, the method increases the efficacy of the preservative agent in the end-use formulation by at least 0.5 log reduction, preferably by at least 1.0 log reduction.

These and other aspects will become apparent upon review of the detailed description provided herein.

It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention. It is further to be understood that all embodiments and definitions provided herein in the context of the preservative composition are intended to likewise define all other aspects of the present invention such as the inventive formulations, products, methods and uses.

In general, the present invention is directed to a preservative composition. As used herein, the term “preservative” means a biocidal agent or biocidal composition which is intended to be blended with into an end-use formulation, such as personal care formulations, cosmetics, home care formulations, and health and hygiene products, to prevent microorganisms from destroying the end-use formulation or making the end-use formulation unusable for the particular purpose for which the end-use formulation was developed.